Physical distribution using ID tags has been attracting public attention in recent years. The ID tag has a memory storing information on commodities, information on distribution history of commodities or the like, and is allowed to access the memory at any time when an external signal is received. A system using the ID tag enables an efficient management never available before.
On the other hand, this sort of system, capable of linking the product information with private information, is apprehended to invade consumers' privacy. For example, when a consumer buys a product having an ID tag integrated therein, it is anticipated that information in the tag may be read by a malicious third party, and this raises a possibility of tracing to what purpose the product is used, or what kind of products the customer carries.
As a preventive measures against such invasion of privacy, there is on-going development on a mechanism of nullifying functions of the ID tag.
Patent Document 1 describes an ID tag having such nullification mechanism. The nullification mechanism described in this document is composed of a fuse, and can disable the ID tag by allowing over-current to flow through the fuse to disconnect it.
Patent Document 2 describes a label having, as a nullification unit, a material which can be turned into electro-conductive by heating.
[Patent Document 1] Japanese-Laid Open Patent Publication “Tokkaihei” No. 8-55205; and
[Patent Document 2] Japanese-Laid Open Patent Publication “Tokkai” No. 2001-134732.